From: Kevin Wolf <mail@kevin-wolf.de>
Date: Fri, 10 Sep 2010 10:27:03 +0000 (+0200)
Subject: vvfat: Fix double free for opening the image rw
X-Git-Tag: v0.13.0-rc3^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=345a6d2b54f0c3705a088e626d24e9376ff4f233;p=thirdparty%2Fqemu.git

vvfat: Fix double free for opening the image rw

Allocation and deallocation of bs->opaque is not in the control of a
block driver. Therefore it should not set bs->opaque to a data structure
used by another bs, or closing the image will lead to a double free.

Signed-off-by: Kevin Wolf <mail@kevin-wolf.de>
(cherry picked from commit 0af1e52e93bf5da63b15f1f9596dd4c076da07dc)
---

diff --git a/block/vvfat.c b/block/vvfat.c
index 5898d664b04..07720371c9f 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -2768,12 +2768,12 @@ static int vvfat_is_allocated(BlockDriverState *bs,
 
 static int write_target_commit(BlockDriverState *bs, int64_t sector_num,
 	const uint8_t* buffer, int nb_sectors) {
-    BDRVVVFATState* s = bs->opaque;
+    BDRVVVFATState* s = *((BDRVVVFATState**) bs->opaque);
     return try_commit(s);
 }
 
 static void write_target_close(BlockDriverState *bs) {
-    BDRVVVFATState* s = bs->opaque;
+    BDRVVVFATState* s = *((BDRVVVFATState**) bs->opaque);
     bdrv_delete(s->qcow);
     free(s->qcow_filename);
 }
@@ -2816,7 +2816,8 @@ static int enable_write_target(BDRVVVFATState *s)
 
     s->bs->backing_hd = calloc(sizeof(BlockDriverState), 1);
     s->bs->backing_hd->drv = &vvfat_write_target;
-    s->bs->backing_hd->opaque = s;
+    s->bs->backing_hd->opaque = qemu_malloc(sizeof(void*));
+    *(void**)s->bs->backing_hd->opaque = s;
 
     return 0;
 }